Combination/Permutation

[jessicamuniz]

Hi there, here is simple one, but can somebody explain it to me please. I am still trying to understand the combination / permutation problems.

How many ways can 3 different coins be placed in 2 different bags?





Ans 8
Thanks in advance

[xyzabc123]

let the coins be a nickel, a dime and a quarter.
if none of them is placed in the 1st bag and the rest in the second, we get 1 combinations.
if one of them is placed in the 1st bag and the rest in the second, we get 3 combinations.
if two of them are placed in the 1st bag and the rest in the second, we get 3 combinations.
if all three of them are placed in the 1st bag and nothing in the second, we get 1 combinations.

Sum them all up and you get 8.